dublicated charge on my phone number

hi, i have switched frim At&T to TMobile last Month

to be honest the worst service ever

TMobile is charging me for single line twice 

as postpaid and prepaid, 

no one from TMobile were able to resolve this very Comlicated issue after I called so many time and called my BaNk capital one to refund me for dublicated fees for a single line  570 580 8683